RFR: 8284495: [testbug] Adapt nsk tests to the RISC-V platform

[Feilong Jiang]

Add riscv which don't have shared memory connector.
Following tests passed with this patch and [CODETOOLS-7903138](https://github.com/openjdk/jtreg/pull/66):

- vmTestbase/nsk/jdb/options/connect/connect003/connect003.java
- vmTestbase/nsk/jdb/options/connect/connect005/connect005.java
- vmTestbase/nsk/jdb/options/listconnectors/listconnectors001/listconnectors001.java
- vmTestbase/nsk/jdi/AttachingConnector/attach/attach002/TestDescription.java
- vmTestbase/nsk/jdi/AttachingConnector/attach/attach005/TestDescription.java
- vmTestbase/nsk/jdi/AttachingConnector/attachnosuspend/attachnosuspend003/TestDescription.java
- vmTestbase/nsk/jdi/LaunchingConnector/launch/launch002/TestDescription.java
- vmTestbase/nsk/jdi/LaunchingConnector/launch/launch004/TestDescription.java
- vmTestbase/nsk/jdi/ListeningConnector/accept/accept002/TestDescription.java

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Commit messages:
 - [testbug] Adapt nsk tests to the RISC-V platform

Changes: https://git.openjdk.java.net/jdk/pull/8137/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8137&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8284495
  Stats: 7 lines in 1 file changed: 6 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8137.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8137/head:pull/8137

PR: https://git.openjdk.java.net/jdk/pull/8137